Flat cables are well known and are used in a variety of applications where multiple electrical connections are to be made between pieces of electrical equipment. The flat orientation of the conductors allows individual conductors to be readily identified when connections are being made or when end connectors are being attached. Conventionally, flat cables are made by extruding the insulating material onto the parallel conductors.
Conventional extrusion suffers from a number of disadvantages, particularly where high performance insulation is required, e.g. in the defence industry. Firstly, extruded flat cables are very resistant to bending in a direction parallel to the plane of the cable. This makes it difficult to form conventional flat cables into pre-configured wiring harnesses, and means that the flat cable must be routed in situ. It would be desirable to be able to produce a flat cable construction which could be bent in any direction, such as to allow the production of "drop-in" pre-configured wiring harnesses, particularly where it is difficult to route cables in situ due to restricted access or space limitations.
A second disadvantage is that such extruded insulation material does not necessarily give the best mechanical and electrical insulation properties. Also in order to safeguard the integrity of the insulation, the thickness of extruded insulation tends to be greater than, for example, that of tape-wound insulation. Insulating tapes can be processed, such as by pre-stretching in order to provide the desired mechanical and electrical properties.
It would therefore be desirable to provide a flat cable construction which mitigates some or all of these disadvantages.
U.S. Pat. No. 3 582 537 discloses a woven ribbon cable wherein a woven lattice structure holds a plurality of insulated conductor wires in a given spaced parallel relationship and has its warp and weft members bonded to each other at the intersections thereof.
W091/17551 discloses an electrical insulating composite material comprising an intimate admixture of a thermoplastic copolymer of tetrafluoroethylene and perfluoro (propyl vinyl ether) and coagulated dispersion type polytetrafluoroethylene (PTFE), or of porous expanded PTFE. Tape made from the composite material may be wrapped around a conductor and sintered to fuse the overlapping areas of the tape together.
U.S. Pat. No. 3 654 381 discloses a flat cable woven with a warp consisting solely of conductors. The weft threads are woven directly into the conductors to form the final woven cable.